Soldering, again

To check the motor rotation of Arduino code, I observed the movement by marking a line on surface.

from Doyeon Kwon on Vimeo.

But the power was too weak and unstable, so it was hard to control my model. I saw the bottom of Adafruit motor shield, and I found parts where soldering was wrong.

So I soldered again.
After that, it reduced a little bit of the twitch that kept on doing.

from Doyeon Kwon on Vimeo.